acme: if account key was revoked, generate new account key

the plan was to migrate only specific keys but this allows us the
flexibility to revoke keys after the release (since we have not
gotten response from DO about access to old 1-click images so far).

src/blobs.js

@@ -54,10 +54,6 @@ async function clear() {
 }
 
 async function generateSecrets() {
-    const acmeAccountKey = safe.child_process.execSync('openssl genrsa 4096');
-    if (!acmeAccountKey) throw new BoxError(BoxError.OPENSSL_ERROR, `Could not generate acme account key: ${safe.error.message}`);
-    await set(exports.ACME_ACCOUNT_KEY, acmeAccountKey);
-
     debug('generateSecrets: generating dhparams.pem');
     // https://security.stackexchange.com/questions/95178/diffie-hellman-parameters-still-calculating-after-24-hours
     const dhparams = safe.child_process.execSync('openssl dhparam -dsaparam 2048');